This invention relates to improvements in linerless bottle caps.
In the provision of caps for bottles intended to contain liquids, particularly alcoholic beverages, the cap usually includes a compressible sealing liner for abutment against the annular rim about the incipient mouth of the neck of the bottle to provide a tight seal despite imperfections in the surface of the annular rim.
I am aware that others have previously proposed use of various types of sealing protuberances as depending from the inner surface of the top of a bottle cap in place of the use of a compressible sealing liner. For instance, as shown in U.S. Pat. Nos. 2,886,198; 3,053,406; 3,074,579; 3,151,757; 3,215,297; 3,255,909; 3,232,470; 3,370,732; 3,844,439; and 4,122,965. As may be expected, such sealing protuberances are in the nature of a sealing ring or sealing rings, of various cross sectional configuration and arranged in various attitudes of extension from the top and/or the skirt of the bottle cap. Thus, as shown by these prior patents, criticality of sealing capability is a function of cross sectional configuration and attitude of the sealing rings of a linerless bottle cap.
Considering that, after being tightened onto a bottle, the linerless cap may not be removed for some time, during which it may be further stressed by top loading when in storage or in transit, it can also be appreciated that the degree and amount of flexure required of the sealing ring or rings should be such as to avoid compression by cold flow movement and to provide a bottle cap having reasonably consistent application and removal torque and, preferably, less application torque for re-sealing. Here again, the amount or degree of compression or flexure required of the bottle cap sealing ring or rings is a function of the cross sectional configuration and attitude of the sealing rings of a linerless bottle cap.
It is thus a primary object of this invention to provide a linerless bottle cap having a plurality of concentric sealing rings, the cross sectional configuration and attitude of the sealing rings thereof being such as to provide optimum sealing characteristics, minimal compression by cold flow movement and a degree of flexure facilitating consistent bottle cap application and removal torque and less application torque for re-sealing.
A further object is the provision of a linerless cap having concentric sealing rings spaced to coact with each other in providing a seal formed not only in relation to abutment of the sealing rings with the annular rim about the incipient mouth of the neck of a container, but also as a derivative of abutment of the sealing rings with each other.
Other objects and advantages of the invention will become apparent from the following detailed description, taken in connection with the accompanying drawing, and in which drawing: